Novel unsymmetrical leuco-TAM, (2E, 2′E)-2,2′-{(E)-4-phenylpent-2-ene-1,5-diylidene}bis(1,3,3-trimethylindoline) derivatives: Synthesis and structure elucidation

Novel Fischer’s Base Analogous of Leuco-TAM and TAM+ Dyes – Synthesis and Spectroscopic Characterization

“…The unsymmetrical molecule is a distorted version of the well-known three-bladed propeller conformation. (Keum et al, 2011). The inter-plane angles of the aromatic rings A-B, A-C, and B-C in Un-LTAM 4 are 87.4°, 67.5°, and 61.5°, respectively (Fig.…”

“…Numbers of researchers (Gessner & Mayer, 2005) have been interested in developing TAM + molecules. We developed Fischer's base (FB) analogs of LTAM molecules (Keum et al, 2008(Keum et al, , 2009(Keum et al, , 2010(Keum et al, , 2011, whose chemical structures contain a couple of heterocyclic FB rings and a substituted phenyl group on a central carbon of the molecules. The structures and numbering system for the Fischer's base (FB) analogs of LTAMs are shown in Fig.…”

Novel stilbene‐based Fischer base analog of leuco‐TAM – (2E,2′Z)‐{2‐(4‐(E)‐styrylphenyl)propane‐1,3‐diylidene}bis(1,3,3‐trimethylindoline) – derivatives: synthesis and structural consideration by 1D NMR and 2D NMR spectroscopy

“…[1] The x-bands of the extended TAM + were comparable with those of the unextended TAM + dyes, whereas the y-bands were expected to be better chromophores because of the [20,21] and Ma et al [32] 4-CHO 60. extended conjugation from the nitrogen of the FB ring to the central stilbene ring, as shown in Scheme 4. Detailed UV-Vis spectroscopic studies of various St-TAM + dyes in various organic solvents will be presented in the near future.…”

“…Next, St-LTAM compounds (St-LTAM) 1-6 were prepared by treating an excess of 5-substituted FB with the SBA derivatives thus prepared, as shown in Scheme 2, by employing the procedure reported by Keum et al [20][21][22] For the synthesis of TAM + dyes, dichloro dicyano quinone was first added to a solution of St-LTAM in benzene. Second, the solution was stirred for 1.5 h at room temperature.…”

“…[20][21][22] A number of LTAM molecules containing a central carbon bearing two FB fragments and one aryl ring such as phenyl and pyridinyl have been reported previously. The FB moiety, whose skeleton contains a conjugated enamine moiety, is regarded as an active methylene groupcontaining indole.…”